The invention relates to a packaging of pliable biodegradable material, particularly cardboard, provided with a pouring spout.
Packages used particularly for handling consumable granular or pulverulent products such as for example: flour, sugar, rice, must be at the same time easy to use, low in cost and hermetically sealable.
There exists packaging comprising in the central region of one wall a substantially rectangular retractable pouring spout, of metal or a rigid material separate from the material of the packaging. This packaging is satisfactory but has the following drawbacks: on the one hand, during recycling of used packaging, the pouring spouts of rigid material cannot be recycled at the same time as the packaging of pliable material; on the other hand, when the packaging of biodegradable material is not recycled, the non-biodegradable pouring spouts constitute a source of pollution of the environment.
But when rectangular pouring spouts are made of cardboard, the resistance to crushing of the packaging decreases substantially because the pouring spout is not of a rigid material and does not contribute to the stability of the packaging.
The documents DE 38 32 544 C1 and DE-GM 74 12129 seek to overcome the reduction of resistance to crushing by connecting the rectangular pouring spout to the corners of the packaging. These solutions however dictate the positioning of the pouring spout or its dimensions and do not permit obtaining resistance to crushing upon piling of the packages to great heights, with a simple design and economical manufacture.
The document FR 2.106.720 describes a box for packaging of cardboard comprising an opening for sampling which can be closed by a pivotal closure flap forming in open position a pouring spout. The flap comprises a closure portion and two tongues pivoting about corresponding lines of articulation.
The document U.S. Pat. No. 3,586,910 describes a box comprising a retractable cardboard pouring spout on a wall of the box. This pouring spout has in its open position the shape of a small channel sliding on the corresponding edges of the opening; this pouring spout is not adapted to pouring powders or flour susceptible of flowing over the edges of the channel.
The document U.S. Pat. No. 4,953,781 describes a packaging box comprising a pouring spout of folded-back cardboard provided with a grasping tongue: the elasticity of the folds of this pouring spout gives rise to imperfect closure of the pouring spout and a loss of hermetic seal.